Some mechanics are ASE certified, which is a standardized method of testing skill and knowledge level. While it’s not required by law for a mechanic to be certified, some companies only hire or promote employees who have passed ASE tests. The technology used in automobiles changes very rapidly and the mechanic must be prepared to learn these new technologies and systems. The auto mechanic has a physically demanding job, often exposed to extreme temperatures, lifting heavy objects and staying in uncomfortable positions for extended periods. They also deal with exposure to gasoline, asbestos, and other toxic chemicals.